/* body {
  height: 100vh;
} */

header {
  display: flex;
  align-items: center;
  background-color: #20617c;
  padding: 0.5rem 1rem;
}
/* 
按钮菜单
*/
.btn_menu{
  position: relative;
  display: flex;
  align-items: center;
  width: 1.5rem;
  height: 1.25rem;
  align-self: center;
  margin-right: 1rem;
  cursor: pointer;
}

/* 菜单横线 */
.line{
  flex-shrink: 0;
  width: 1.5rem;
  height: 0.1rem;
  background-color: white;
}

.line:nth-of-type(1) {
  position: absolute;
  left: 0;
  top: 0;
}

.line:nth-of-type(3) {
  position: absolute;
  left: 0;
  bottom: 0;
}

.btn_menu .menu-line-tr {
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.menu-line-tr-1 {
  transform: translate(-50%, -50%) rotate(45deg) !important;
}

.menu-line-tr-2 {
  transform: translate(-50%, -50%) rotate(-45deg) !important;
}


/* title */
header h2{
  margin: 0;
  text-transform: uppercase;
  word-spacing: 0.33rem;
  font-family: sans-serif;
  text-align: center;
  color: white;
}





.portrait {

}

/*
 container
 */
.container{
  width: 100%;
  position: relative;
  z-index: 0;
  /* display: flex;
  align-items: flex-start; */
  transform-style: preserve-3d;
  perspective:5000px;
}
/* 
menu
*/
.menu{
  display: flex;
  flex-direction: column;
  position: absolute;
  left: 0;
  top: 0;
  z-index: 2;
  transform-origin: 0 50%;
  transform: translateX(-100%);
  background-color: #244452;
}

.menu a{
  padding: 0.5rem 1rem;
  color: white;
  transition: border-color 0.15s, color 0.15s ;
  font-family: sans-serif;
}

.menu a:hover {
  background-color: white;
  color: #244452;
}